What is DNS in simple words. What is DNS and how DNS servers ensure the Internet works Dns how it works

DNS - what is it and what is it used for?

The Internet is a countless number of physical devices (servers, computers, tablets, etc.) connected to each other in a network. Any website on the Internet is actually located on a physical device. Each device has its own unique number - an IP address of the form 123.123.123.123.

To get to the site, you need to know the IP address of the device on which the site is located. Now imagine how many sites you visit per day and how many numbers you would have to remember. Of course, this is unrealistic. Therefore, for the convenience of working on the Internet, a domain name system was created in the 80s - DNS(Domain Name System). Its meaning is that each digital IP address is assigned a clear alphabetic name (domain). When you enter a domain name in your browser, DNS servers convert it to an IP address..58.116.30.

What are DNS servers for?

The Domain Name Service works thanks to DNS servers. It is these vital “programs” that store correspondence tables of the form “domain name” - “IP address”. In addition, DNS servers serve to store domain resource records: There are a huge number of DNS servers on the Internet, each performing its own function in common system. The Domain Name System service is necessary so that we can easily find our favorite sites without remembering strings of numbers.

So, you enter the name of the site in the address bar and press Enter. In those very seconds before the site is displayed on your screen, DNS servers work without sparing themselves. Let's see what DNS servers do. Follow the arrows.

1. 1.

   After receiving a domain name from you, the computer contacts the DNS servers of your Internet service provider ( arrow 1). The provider's DNS servers look for the IP address in the cache. If found, they give you an IP address ( arrow 6) and using this IP address your computer accesses the server on which the site is hosted ( arrow 7).The site is displayed on the computer screen. That's all :)

2. 2.

   If the “domain-IP address” pair is not in the cache of the ISP’s DNS servers, the provider’s DNS server sends a request to the root DNS servers ( arrow 2). There are only a few such servers around the world, and the information on them is updated several times a day. Root servers report the addresses of the domain's DNS servers ( arrow 3). The ones that need to be registered for a domain after registration and that store all up-to-date information about the domain (IP address, resource records, etc.).

3. 3.

   Having received the addresses of the domain DNS servers, the provider makes a request to one of them ( arrow 4), receives the long-awaited IP address in response ( arrow 5), stores it in the cache (so that you don’t have to contact the root DNS server every time) and finally reports this IP address to your browser ( arrow 6).

4. 4.

   And only now the satisfied browser uses the IP address to contact the server on which the site is located ( arrow 7), and displays the site for you on your computer screen ( arrow 8).

Why register DNS servers for a domain?

Let's say you have registered a domain. So far, no one except you knows about this. In order for the Internet to know about the existence of your domain, you need to select and register DNS servers for the domain. They will tell other Internet DNS servers about your domain. So let's remember: registered a domain - specify DNS servers!

DNS servers are most often prescribed in pairs. One of the DNS is the primary, and the remaining servers, which can be from 1 to 12 for each domain, are called secondary. This is done for better fault tolerance: if one DNS server fails, the domain and website will continue to function.

Why don't domains start working right away?

The ISP's DNS servers are updated once a day (). If you have just registered or changed DNS servers, you will have to wait 24 hours. Changing the DNS server is fraught with the temporary absence of a working website. After updating the DNS, the site will become accessible. If the site does not work, here are the instructions to help you: .

Hello dear readers of the site! Have you ever wondered how your browser finds sites on the Internet?

What’s so complicated here, you say, the user enters the domain name of the desired site in the address bar and the browser downloads content from the specified address.

In fact, a domain is not a website address on the Internet at all, but something like a subscriber’s nickname, which you used to identify your friend in the phone book of your smartphone.

For example, to instantly find out who is calling, you attach your friend's nickname to the phone number. During a call, the smartphone display does not display the digits of the cell number, but the name under which you have entered the interlocutor in the phone book.

The same thing happens with website domain names. However, let's understand it from the very beginning and in detail.

Why do we need DNS servers on the Internet?

In the early days of the World Wide Web, connected computers were few and far between, and the users were experienced professionals.

Each connection point (client computer) was identified on the network using . What stands for Internet Protocol Address is the Internet protocol address.

An IP address looks something like a cell phone number:

• 59.109.189
• 59.110.48
• 59.109.207

Over time, the number of Internet users increased significantly and then, to facilitate the task of surfing the Internet, it was proposed to associate digital IP addresses of sites with verbal domain names.

To ensure that every digital IP address on a website is assigned a human-readable name, the Global Domain Name System was created.

In English Domain Name System or for short DNS.

The Domain Name System is a distributed infrastructure of a large number of servers located throughout the planet. This DNS server structure is built on the principle of hierarchical subordination.

• Top-level domain name servers – COM, RU, and so on.
• Servers with lists of second-level domain names – google.com.
• Third-level domain servers – api.google.com.

The highest position in the hierarchy is occupied by root DNS servers, which store lists of top-level domain name servers. There are just over 10 root DNS servers around the world.

Speaking in simple words, the domain name system functions as a global address desk for the World Wide Web.

Local DNS branches store the IP addresses of websites associated with domain names that belong to a given region. If it is impossible to find the site address for the requested domain name on the local DNS server, the request is delegated to the next level of the system.

And in this way, the search for an IP address using the domain name specified by the browser occurs until the desired site is found on one of the DNS servers responsible for storing it.

An example of how a browser finds a site

To understand how it all works, let's look at a specific example of searching for a site.

• The user types a domain name in the address bar or clicks on a link to a specific web page.
• First of all, the browser accesses its own cache and checks whether this resource has been visited before.
• If the website you are looking for has already been visited before, then its IP address is already stored in and there is no need to waste time contacting DNS servers. In this case, caching is used as a method to speed up Internet searches.
• If the searched domain is not found in the browser cache, then the search continues in the records operating system. If the site is not recorded there either, then a call to the Internet provider’s server occurs.
• The Internet provider, in turn, collects information about the web resources visited by each user in its own cache. This is also done to speed up the search and improve the comfort of the service.
• And only after the domain specified in the browser search line is not found in the cache of the browser, operating system or Internet provider, the general system of DNS servers is contacted.
• Next, the domain name is searched through the hierarchy of the DNS system from top to bottom.
• In this case, a search using the DNS server system is aimed at identifying the delegated NS server of the domain name registrar from which the owner of the site in question rented the domain.

Such a rather complex algorithm for searching for a site’s IP address by domain name is obtained because today there are already more than a billion Internet resources on the World Wide Web.

Hosts file

It was mentioned just above that records of website addresses may be located in the computer’s operating system. Indeed, among the system files there is a document named Hosts.

This is a regular text file, but does not have a txt extension. The fact is that Hosts files can be present on computers of other operating systems, not just Windows.

On alternative OSes, file extensions may not match, so we agreed to use the Hosts text document without specifying the file type at all.

The Hosts file contains a list of comparisons between domain names of Internet resources known to the user and their IP addresses.

• 127.0.0.1 localhost

First, the IP address is written down, and then the name of the Internet resource.

It is believed that the Hosts file is archaic. This file was used in the old days when computers had little power and every opportunity to speed up processes was used.

The above entry from the Hosts file means that the user’s computer itself is located at this IP address. In most cases, on modern personal computers this entry is the only one.

Sometimes advanced users, in order to block visits to a site, add an entry to the Hosts file in which they compare the domain name of the unwanted resource with the IP address of the computer.

If a browser makes a request for this domain name, the local system is contacted and it is impossible to go to the site.

For example, a user does not want his children to visit any websites. Then you can edit the Hosts file and specify local host as the IP address of the unwanted site.

The Hosts file is sometimes used by hackers to redirect the user to . If a user visits an infected site and downloads a virus from there, then this virus can make changes to the Hosts file entries.

For example, the domain name of a reliable online bank will be associated with the IP address of a fraudulent resource. By typing the bank address in the browser, the user will be taken to a scam site and lose his money.

Today, the Host file has lost its significance and may not contain any entries at all. This will not affect the functionality of the computer or the ability to surf the Internet.

What are NS servers

In a distributed system of hierarchical domain names, NS servers are allocated, which store the most complete information about a specific Internet resource. These NS servers are the final (delegated) ones in the entire address chain in relation to a specific site.

To ensure the reliability and uninterrupted functioning of the site, information about it must be recorded on at least two DNS servers.

In this screenshot we can see that my website domain that I obtained from a partner registrar Link-Host recorded on four NS servers at once. One of these NS servers is designated as the main one (Master), the rest are subordinates (Slave).

As a hosting provider, which ensures the uninterrupted operation of the site and which provides free ones, I chose, which I advise everyone.

How to set (change) DNS for a domain

How to do this practically?

• Log in to the site control panel on your hosting.
• Go to the domain management section.
• Open the “DNS servers and zone” interface.
• If the domain name was registered on the same hosting where the website is published, NS servers are registered automatically.
• To specify arbitrary NS servers, you need to uncheck the “Automatically use registrar NS servers” checkbox and enter the desired services.

The algorithm for assigning NS servers may vary depending on the specific hosting, domain registrar and site control panel.

Domain data is updated on DNS servers not instantly, but every other day, in some cases within 72 hours.

So you will have to wait until the site becomes available to users after delegating the domain to certain NS servers.

What does the DNS server not responding mean and what should you do?

Life modern man without the Internet is unthinkable. And then one day the browser stops finding sites on the Internet. No web page is displayed upon request.

You try to launch other Internet browsers, but they don’t work either.

The first thought is to urgently call the telecom operator and find out why the Internet is not working and when the fault on the line will be corrected.

Real practice has shown that most problems with the Internet are not caused by technical violations of the Internet provider, but by failures in computer settings and local software problems.

To figure out why there is no Internet connection, run network diagnostics using Windows.

• Hover your mouse over the network connections icon in the taskbar and right-click.
• The context menu will open.

• Click on "Diagnose problems".

If, based on the diagnostic results, a notification “DNS server is not responding” appears, this means that the following problems can be assumed:

• Technical faults on the provider's side.
• Malfunctions or failure of network equipment settings: modem, router, router.
• Computer malfunction or incorrect settings.

First, try rebooting your router and computer. If the problem persists, you should diagnose the devices by eliminating intermediate elements.

1. If possible, try connecting your computer to the Internet through an alternative network device. For example, use a modem instead of a router. If the Internet appears after connecting another network device, then you will know that the problem is in the router.
2. Connect the router to another computer. If the Internet is available, then there is a problem with the first computer.

If the router is fine, remember what you did with the computer before the problem occurred.

• The reason for the Internet disruption may be the installation of some new software.
• Some computer applications are deeply embedded in the registry and independently make changes to system settings.
• Restore the operating system to the state before the installation of suspicious applications.
• If after completing the recovery process and restarting the computer the Internet works normally, the problem was in the application.

If only individual websites are unavailable, the problem may be that the operating system cache contains incorrect IP address and domain name mappings.

In this case, you should clear the cache. To clear the cache, you need to use the Windows Command Prompt. If you are not an advanced user and do not know how to do this, contact a specialist to avoid causing harm to your computer.

You can uninstall and “cleanly” reinstall the software and drivers of network devices – modem or router. After new installation reconnecting to the Internet, searching for a DNS server and network settings will be performed automatically.

You should only manually configure a network if you know exactly how it’s done. Experimenting at random is not recommended; you can ruin both your computer and network equipment.

Call hotline Internet provider and check if there is a current disruption on the line and when the problem will be fixed.

If none of the above helps, you should contact a service center specialist for help.

What is a DNS server, how does a DNS server work?

What is a DNS server

A DNS server is a server that allows you to convert symbolic domain names into IP addresses, and vice versa.

A domain is a specific zone in the domain name space, which must be assigned at least one IP address.

How DNS works

The DNS service is used to map a domain name to an IP address. The DNS system consists of many servers at different levels; each network must have its own DNS server, which contains a local database of DNS records.

How it works:

• The client makes a request to the local DNS server, for example, you typed the website address in the address bar of your browser;
• If the local DNS contains this entry, then it gives the answer. In our example, the browser will receive the IP address of the site and contact it.
• If the local DNS does not have the required entry, then it contacts the next DNS server, and so on, until the entry is found.

One IP address can be associated with many domain names - this is called virtual hosting. But one domain name can be assigned multiple IP addresses, usually to distribute the load.

DNS Server Records

U DNS servers There are several types of records, let's consider them:

SOA Record creates a zone for a domain, for example, we need to add the domain exempl.com, then we first need to create a SOA record, which will indicate on which server the information about this domain is stored. The SOA record has several parameters:

1. Serial - serial number of the zone. It increases every time changes are made in a given domain; this is necessary to detect changes from the secondary DNS server and determine the need to update its cache.
2. Refresh - update period. The period in seconds after which the secondary DNS server should check the serial number of the primary server for changes, and update the data if necessary.
3. Retry - repeat the update. Sets the frequency of attempts to update the secondary DNS when connecting to the primary fails. Set in seconds.
4. Expire - the period for storing primary DNS data on the secondary, in case of unsuccessful attempts to connect and update data.
5. TTL is the lifetime of records for this zone in the cache of secondary DNS servers. For example, the lifetime A of a given zone record on secondary servers. If the data changes frequently, it is recommended to set the value to a small value.

NS entry(name server) - points to the DNS server for this domain, that is, to the server where A records are stored.

example.com IN NS ns1.ukraine.com.ua

Record A(address record) - this record indicates the IP address of the domain.

example.com IN A 91.206.200.221

CNAME record(canonical name record) indicates a synonym for this domain, that is, this domain will be assigned the IP address of the domain to which this record refers.

example.com IN CNAME xdroid.org.ua

MX Record(mail exchange) points to the mail server for this domain.

example.com IN MX 10 mail.example.com

An additional digit in front of mail.example.com indicates the priority value - a smaller digit means a higher priority.

PTR Record(Pointer) - is the reverse of the A record. Searching for an IP address by domain is carried out using the A record, and searching for a domain by IP address is carried out using PTR records. It makes sense to set PTR records only on physical hosting, since on virtual hosting all names have the same IP.

This is not a complete list of DNS server records, but we have looked at the main records.

Full list of DNS records:

1. SOA (start of authority record)
2. NS (name server)
3. MX (mail exchange)
4. A (address record)
5. CNAME (canonical name record)
6. TXT (Text)
7. PTR (Pointer)
8. SRV (Server selection)
9. AAAA (IPv6 address record)
10. AFSDB (AFS data base location)
11. ATMA (ATM address)
12. DNAME (Name redirection)
13. HINFO (Host information)
14. ISDN (ISDN address)
15. LOC (Location information)
16. MB (Mailbox)
17. MG (Mail Group Member)
18. MINFO (Mailbox or Mail list info)
19. MR (Mail rename)
20. NAPTR (Naming Authority Pointer)
21. NSAP (NSAP address)
22. RP (Responsible Person)
23. RT (Route through)
24. SPF (Sender Policy Framework)
25. SRV (Server Selection)
26. X25 (X.25 PSDN address)

Hello, dear readers of the blog site.

Today I will talk about what DNS servers are. We will talk about this technology and understand how it works. It is with the help of this system that the entire Internet operates. And every webmaster must know the meaning of this abbreviation. So let's get started!

DNS servers are a very important component of the entire system that makes the Internet work. Roughly speaking, this is a system that is responsible for domains - the very website addresses that we use every day. This system can be compared with an account book or directory, where the addresses of residents of a certain city or street are listed.

The concept itself stands for domain name system. This very system connects domains and IP addresses of servers on which some information is stored.

The Internet consists of a huge number of servers (computers) that are interconnected. Each server has its own IP address.

IP consists of a specific set of numbers, which represents the server identifier. Each such server has a static, that is, stable IP address.

Let's say, if you need to go to a site using some URL, then you will not enter the IP address of the server on which the files of this resource are stored. You just need to enter a certain well-known domain name (URL like site.ru), after which your browser itself will go to the desired server and open the desired site. The DNS system is responsible for this process. It should direct users to the right place. A kind of navigator from the world of the Internet.

Domains typically consist of letters, numbers, and symbols. Each of them is unique and consists of the name itself and the domain zone. For example, site.ru, where site is a name or title, and ru is a zone. To use a particular domain, you must first rent it.

After you pay a certain amount to the registrar, the domain will be yours for a certain period of time. You will need to register DNS for this domain so that it is connected to the servers where your sites are located.

If the lease ends and you do not renew it, the domain can be registered again. The new tenant will be able to register other DNS servers there, and then the domain will link to the new site.

By the way, in the world of search engine optimization, domain history is quite important. If the domain was previously rented for a website, then be sure that at first search engines will treat the new project the same way they treated the old one.

In other words, if previously a domain had good behavioral factors, then a new tenant can easily receive traffic and good attitude from search engines. If everything was the other way around, then the site may be promoted very poorly in the PS.

Let's sum up some intermediate results:

1. The Internet consists of a huge number of servers that are interconnected and have their own unique numeric addresses (IP or MAC).
2. DNS (Domain Name System) is used for easier interaction between users and these servers. Each domain can be associated with some server; the user needs to know the domain name, but not the numeric IP address itself.
3. Over time, different IP addresses may be assigned to a domain. That is, if now a certain domain name leads to one site, then in a year it may be free or lead to a completely different one.
4. DNS is simply a system that browsers access when a user enters a URL. After a person enters a certain type of domain into the address bar, the browser accesses this system and receives from it the IP address of the desired server.

I hope you get the gist of the above. Everything is quite simple and clear.

By the way, domain name management systems have not always existed. Previously, when the Internet had just appeared, a special file was used to link between the domain and the server address, which was stored on each computer. This file was called hosts, and all domains and associated IP addresses were registered in it.

When a person tried to navigate to a certain domain through a browser, a request was made to this same hosts file, and if the entered domain name was there, the browser was redirected to the IP, which was also listed there.

When there was no DNS yet, such files could contain thousands of records with domain names and the necessary addresses. Naturally, this approach was not convenient, and then people came up with DNS. Using this system, people could link domain names and desired addresses. Hosts were no longer needed.

However, now it is still available on every PC. Usually the host contains records about some special domains, such as an update server or a local computer address.

By the way, even now, when a person begins to enter a domain name into the address bar of a browser, this same browser first checks the hosts file to see if it contains the required entry. If there is no entry (which almost always happens), the browser starts connecting to the nearest DNS server. And now there he finds the desired entry with the address. Next, the browser connects to the address and provides the user with the necessary content.

The hosts file is a priority; it is accessed first. If the required entry is found in the file, the system will not connect to the remote DNS.

And this is how attackers can spoof website addresses. They simply enter a file with a known domain but a fake IP address using viruses. The user follows the link, it takes him to the address specified in the file. The browser does not connect to any servers and simply displays the content specified in hosts.

If attackers want to deceive the user, they will simply make an exact copy of the desired site, but with minor changes. For example, they will replace password fields, where there will no longer be encryption. With the help of this fraud, they will be able to steal the user’s passwords, and the user will not be able to suspect anything. This phenomenon is called phishing, and you need to be wary of it.

To prevent this from happening, you should check your hosts file frequently. There should be no unnecessary entries. If there's anything in there that doesn't belong in there, especially with domains you use frequently, you can safely erase those entries because they put your personal information at risk.

It’s even better if you use antiviruses, which will check the contents of the file with each scan and, in the event of any activity from viruses, will quickly block everything and put it in order.

DNS and Internet

What I described above is just a very simple example where there were several variables: the user and his browser, a DNS server that distributes domains and addresses, and some remote server on which the information is stored. In reality, this scheme can be much more complicated, because there cannot be one DNS server for the whole world. There are thousands, millions, and maybe even more. They are all connected and constantly exchange information.

If a user wants to connect to a site, then his computer first contacts the nearest DNS server so that it redirects to the root one - the one where data about other servers is stored (let me remind you, there are a lot of them and they are all connected in a certain way) .

The root server may make several more requests before it gets to the desired DNS, where the desired address itself will be stored. The scheme is really quite complicated, because the Internet itself is very vast, one might say, limitless.

Also, when exchanging data, the NS servers of the hosting on which a particular site is located can play a very important role. NS servers can provide information about the IP addresses of all sites that are on the host. Hosting services can contain a colossally huge number of websites. Sometimes this number amounts to hundreds and thousands. Each such site has its own thread, which is carried out by the hosting NS servers.

When you enter this address into your browser, this is what happens.

Let's look at this process in more detail.

1. First, your computer or any other device connects to the provider's DNS servers.
2. Next, this domain is transferred from the DNS provider to the root server, where, as an issue, there will be NS hosting addresses to which the domain was linked. I already talked about this; a domain can be linked to NS servers.
3. Next, the domain is transferred to these same NS servers that we received from the root DNS server. Already from NS we receive the IP address of the server we need.
4. This same address is transmitted to the computer, after which this computer connects to the server. Information is transmitted from the server in the form of site content or something else.

This is roughly how this whole system works when we talk about the operation of web resources. In principle, there is nothing complicated here. It is enough to simply understand the essence.

Domains and NS servers

Now I’ll tell you a little more about NS servers and the domains that are attached to them.

There are a huge number of different domain names on the Internet. And we are talking specifically about the employed. If we talk, in general, about all possible combinations, then the number will be simply colossally huge. You can come up with an almost infinite number of different combinations based on the fact that a domain can contain letters, numbers, symbols, etc. There are also domain zones, there are a lot of them, so the number of combinations increases.

Free domains that have not yet been registered by anyone do not have an associated NS server. When accessing a free domain, an error occurs. Typically “DNS Error”. Already taken domain names are tied to NS addresses, which may belong to some large host.

The hosting has the same NS addresses, so all domains that are bound to this host have the same NS. Based on the diagram above, we realized that the distribution of IP addresses occurs directly on the hosting servers. It is on the very NS to which we link the domain.

Typically this is an internal distribution system, the operation of which we will not consider. Let's talk better about those cases when a domain is tied to the hosting NS, but the owner is in no hurry to confirm his ownership within the host.

With this outcome, any person who also has a hosting account can assign this domain to themselves. This has already happened to me, to register a domain I used Reg.ru, there I registered the NS of one well-known hosting, but in the hosting itself I did not link the domain to my account. Someone else did it. He set up a redirect to some dubious project.

Thus, with the help of DNS servers, the scammer was able to temporarily steal my domain. Why temporary? It's simple: I could go to the registrar's website and simply change the NS to something else. And everything would stop working for him, after which I could do this operation again and link the domain to my account.

That is, if you simply register the NS of your host when registering a domain, this does not guarantee that this same domain will be linked to the desired web resource. Already within the hosting itself, you must also perform a number of certain manipulations so that NS can send users to the desired IP address.

After registering a domain, if you have already chosen hosting but have not yet created an account there, do not register DNS right away. Fraudsters have special parsers that monitor all domains that are linked to the NS of a large hosting, but have not yet been assigned to any account.

If you registered a domain within your hosting, it will be linked to your account and the necessary addresses automatically. But you may have difficulties transferring your site to another hosting. You will have to make a lot of unnecessary movements that are not entirely justified.

How to change NS servers

Now I will talk about how to change NS when changing host. As an example, we will consider the registrar Reg.ru. But I think that these instructions will be relevant for any other registrar, because they have a similar interface, so there should not be any difficulties.

First, you need to go to your personal account. Next, go to the list of domains, then hover over the NS servers and click on them. A window will pop up listing the NSs to which the domain name is currently associated.

You need to click on the “Change” button, after which you will immediately be transferred to the window for editing addresses.

As you can see, you have a choice here. You can click on one of the first three lines to automatically register DNS Reg.ru. If you need to unlink your domain from your current hosting, you can temporarily link it to a free DNS registrar. You can do this using these three lines.

The first line will simply link your domain to the stub. When clicking on a URL, users will be directed to an empty placeholder with minimal information.

The next line will link your domain name to the Reg.ru virtual host. If you want to use this function, I recommend that you immediately click on this line.

The third will link your domain to the DNS of more advanced and powerful hosting options. You need to use them only if you want to work with this provider and place your resources there.

You can also specify your DNS servers. Two fields will appear where you will need to enter arbitrary addresses. This option is used most often, because many users work with other virtual hosting.

Just insert two addresses, then click on the “Done” button. If more than two addresses are used, then using the special “Add DNS server” button you can add additional fields. We also enter all the necessary addresses, and then click on the button.

The DNS change process is not as fast as we would like. After you save the settings, approximately 24 more hours should pass before all the necessary changes are finally accepted. Until this moment, if you go to the address, you will be thrown either to the old site, or an error will pop up.

By the way, DNS must be updated on the provider's side. If you use a proxy or VPN to open a resource with newly changed DNS addresses, there is a high probability that the domain will immediately transfer you to a new server or site.

But most users will still experience problems connecting to the site with the newly updated DNS. Therefore, consider this point if you decide to change DNS.

If you registered your domain through hosting, then you can also change the NS servers in the control panel to transfer. However, in this case, domain administration will still occur through the hosting admin panel. Transferring a domain name to another registrar will the best option in this case.

Conclusion

I tried to explain in simple words what DNS is and what it is needed for. I hope this article answered all your questions and now you understand how the Internet works a little more.

Understanding this topic is very important, especially in light of recent events. In Russia they want to create an autonomous Internet, and DNS servers will play a key role here. The Russian government wants to create its own nodes, which will be controlled only by it.

This means that all DNS servers will control incoming and outgoing traffic. Is it good or bad - decide for yourself. With the help of this article you will be able to understand the essence of this bill a little more. That's all, have a nice day!

What is DNS, how it works and how to specify or change DNS servers for a domain - 3.5 out of 5 based on 2 votes

DNS - (Domain Names System) Domain Name System - is a network service, on whose servers domain names are matched with digital values their IP addresses.

Let's take a closer look at what DNS is, how it works and how it works.

The Internet is an IP network and each computer on this network has a specific personal number, which is called an IP address. But since it is not convenient to use digital addressing, it was decided to use alphabetic writing of addresses. Therefore, when accessing any sites on the Internet, you enter letters, not numbers. But the problem is that computers can only perceive digital information, that is, a sequence of ones and zeros, and are absolutely unable to understand letter information.

That is why a special service was created on the Internet that converts the alphabetic spelling of addresses into numbers and this service is called DNS (Domain Name System).

The DNS service is a huge database that contains information about the correspondence of a specific domain name to a specific IP address. Visually it can be depicted like this:

There are a huge number of domain names on the Internet and there are more and more of them every day, so you can imagine how huge the database of this service is. Storing such a large amount of information on one server is unreasonable and practically impossible.

But since the Internet consists of subnets, it was decided to split this database and place a certain size of it in each of the subnets. Where IP addresses correspond to domain names only for computers included in a given subnet.

What is NS server

The server that contains all the information about the correspondence of domain names in a specific subnet is called the NS server, which stands for Name Server or name server. Let's look at an example of converting a domain name to an IP address based on a simplified network.

As you can see, on this network there is a computer with an alfa domain with an IP address of 192.55.11.25 and a computer with a beta domain with an IP address of 192.55.11.26, as well as a DNS server itself, which also has a corresponding IP address. Now let’s assume a situation that computer beta needs to contact computer alfa, but it does not know its IP address, only its domain name. However, he knows the IP address of the DNS server which he contacts to find out the IP address of the alfa server. The NS server searches its database and, having found the IP address that matches the alfa domain name, transfers it to the beta computer. The beta computer, having received an IP address, uses it to contact the beta computer.

As you know, all domain names have their own hierarchical structure and are divided into domain zones.ru. com and others. See the material for more details. So, each domain zone has its own NS server containing information about the IP addresses of those domains that are included in a certain domain zone. Thus, this huge database is divided into smaller ones.

DNS Settings

How can you change and specify the DNS server for a domain.

In order for it to load when you enter the address of your website into the address bar of your browser, you need to link the site’s domain name with hosting. To do this, we must inform the DNS service which NS server needs to be contacted, so that it, in turn, looks in its database and tells which server (hosting) the browser should contact.

The DNS server record looks like this:

ns1.yourhosting.ru
ns2.yourhosting.ru

You can find these addresses:

• in the letter sent to you by the hosting provider immediately after ordering hosting;
• in the hosting control panel, for example in the domains section;
• by contacting hosting support.

Now about where they need to be indicated. These DNS server addresses must be specified to the domain that you are going to use as the address of your website. Therefore, go to the website of the domain name registrar where you registered your domain. In domain management, find the DNS server item or DNS Server Management / Delegation, the name may differ depending on the registrar. For example, at the domain name registrar that I use to register my domains, you need to go to the “My Domains” section >> select the desired domain and select “Change DNS servers” from the drop-down list.

After entering this section, a form will open in which you need to enter the appropriate DNS servers. To do this, in my case, you need to uncheck the “Use registrar names” option and then specify ns1.vashhosting.ru in the DNS1 field, and ns2.vashhosting.ru in the DNS2 field. IP addresses may not be specified, so some hosting providers do not issue them. After filling in the fields, click the "Edit" button.

After this, you need to wait some time until the DNS servers are matched. This may take from several hours to a whole day. Therefore, as soon as you specify them, your site will not load.

How to specify your DNS servers for a domain

Sometimes it is necessary to indicate your DNS servers, i.e. DNS servers that are located in the same domain. Almost all of them have their own DNS server service. In this case, for example, for this site, ns1..site is specified as the DNS server.

The following points must be taken into account:

1. If you specify your DNS servers for a domain located in the RU, SU, RF zones, then you must specify its IP address for each DNS server. In this case, each specified IP address must differ by at least one digit; it is not permissible to indicate the same IP.

2. If the DNS servers that you specify for your domain name are in another domain, for example, if for a website domain you specify DNS servers like 1ns.vash-sait.ru or 2ns.vash-sait.ru, then you do not need to specify IP addresses .

3. If you specify your DNS servers for an international domain, then these DNS servers must be registered in advance in the international NSI Registry database. It is not possible to indicate them without registering in this database. When registering with NSI Registry, you will be required to enter IP addresses for each DNS server. Therefore, when specifying DNS servers for a domain, there is no need to specify IP addresses.

Attaching an IP address to a domain

To attach an IP address to a domain, you need to go to the DNS records settings. How to do this will depend on your hosting control panel. For example, in ISPmanager you need to go to the “Domain Names” section, then double-click on the required domain name and specify or edit the following three entries (to create an entry, click on the “Create” icon; to edit, click on the required entry):

For the first entry, enter www in the “Name” field, select A (Internet v4 address) in the “Type” drop-down list, and enter the required IP address in the “Address” field.

For the second entry, enter @ (dog) in the “Name” field, select A (Internet v4 address) in the “Type” drop-down list, and enter the required IP address in the “Address” field.

For the third entry, enter * (asterisk) in the “Name” field, select A (Internet v4 address) in the “Type” drop-down list, and enter the required IP address in the “Address” field.

Video: How the DNS system works

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